Multi-use loading unit

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional and claims the benefit of and priority to U.S. patent application Ser. No. 13/280,880, now U.S. Pat. No. 9,016,539, filed Oct. 25, 2011, the entire disclosure of which is incorporated by reference herein.

BACKGROUND

Technical Field

The present disclosure relates generally to instruments for surgically joining tissue and, more specifically, to a multi-use loading unit for use with surgical instruments.

Background of Related Art

Various types of surgical instruments used to surgically join tissue are known in the art, and are commonly used, for example, for closure of tissue or organs in transection, resection, anastomoses, for occlusion of organs in thoracic and abdominal procedures, and for electrosurgically fusing or sealing tissue.

One example of such a surgical instrument is a surgical stapling instrument, which may include an anvil assembly, a cartridge assembly for supporting an array of surgical staples, an approximation mechanism for approximating the cartridge and anvil assemblies, and a firing mechanism for ejecting the surgical staples from the cartridge assembly.

Using a surgical stapling instrument, it is common for a surgeon to approximate the anvil and cartridge members. Next, the surgeon can fire the instrument to emplace staples in tissue. Additionally, the surgeon may use the same instrument or a separate instrument to cut the tissue adjacent or between the row(s) of staples.

SUMMARY

The present disclosure relates to a surgical instrument having a channel and a removable assembly disposed in releasable engagement with the channel. The removable assembly includes a cartridge body and a support plate. The cartridge body is configured to house a plurality of fasteners or staples therein and includes an engagement structure disposed adjacent a proximal end thereof. The support plate is configured to mechanically engage the cartridge body and includes an engagement structure disposed adjacent a proximal end thereof. The engagement structure of the cartridge body is configured for longitudinal alignment with the engagement structure of the support plate. The engagement structure of the cartridge body and the engagement structure of the support plate are configured to mechanically engage engagement structure of the channel when the removable assembly is engaged with the channel.

In disclosed embodiments, the engagement structure of the channel includes raised bosses, the engagement structure of the cartridge body includes a U-shaped recess, and/or the engagement structure of the support plate includes a U-shaped recess. In disclosed embodiments, the U-shaped recesses of the cartridge body and the support plate include a proximally-facing opening.

In disclosed embodiments, the channel includes a longitudinally-extending slot disposed adjacent a distal end thereof, and the support plate includes an outwardly-extending finger configured to releasably engage the longitudinally-extending slot of the channel.

In disclosed embodiments, the support plate includes an inwardly-extending finger disposed on a distal portion thereof. Here, the inwardly-extending finger is configured to releasably engage a groove disposed on a distal portion of the cartridge body.

In disclosed embodiments, the support plate includes a proximal protrusion disposed adjacent a proximal end thereof. The proximal protrusion is configured to help prevent an actuation sled from prematurely translating distally with respect to the cartridge body.

In certain embodiments, the channel is part of a removable loading unit that includes an anvil assembly.

In a further aspect of the present disclosure, a loading unit for a surgical instrument has an anvil assembly, a channel, and a cartridge assembly. The channel has a boss disposed adjacent a proximal end thereof. The cartridge assembly and anvil assembly are pivotable with respect to one another. The cartridge assembly includes a support plate, and a cartridge body. The support plate is configured to releasably engage the channel and includes a recess disposed adjacent a proximal end thereof. The cartridge body is configured to releasably engage the support plate and is configured to house a plurality of fasteners or staples therein. The cartridge body includes a recess disposed adjacent a proximal end thereof. The recess of the cartridge body is configured for longitudinal alignment with the recess of the support plate. At least one of the recesses of the cartridge body and the support plate is configured to mechanically engage the boss of the channel when the support plate is engaged with the channel.

In disclosed embodiments, the recess of the cartridge body includes a U-shaped recess and/or the recess of the support plate includes a U-shaped recess. In such embodiments, the U-shaped recesses of the cartridge body and the support plate include a proximally-facing opening.

In disclosed embodiments, the channel includes a longitudinally-extending slot disposed adjacent a distal end thereof, and the support plate includes an outwardly-extending finger configured to releasably engage the longitudinally-extending slot of the channel.

In disclosed embodiments, the support plate includes an inwardly-extending finger disposed on a distal portion thereof. The inwardly-extending finger is configured to releasably engage a groove disposed on a distal portion of the cartridge body.

In disclosed embodiments, the support plate includes a proximal protrusion disposed adjacent a proximal end thereof. The proximal protrusion is configured to help prevent an actuation sled from prematurely translating distally with respect to the cartridge body.

In certain embodiments, the loading unit includes a body portion to which the cartridge assembly and anvil assembly are attached the body portion being attachable to the elongate member of a surgical instrument.

The present disclosure also relates to a surgical instrument having a channel and comprising a cartridge assembly, a drive member and a lockout mechanism. The drive member is configured to travel in a distal direction. The lockout mechanism is configured to prevent longitudinal translation of the drive member. The lockout mechanism comprises a latch and a spring. The latch is disposed in mechanical cooperation with the channel and is laterally movable from an initial position to a blocking position. The spring is configured to bias the latch into the blocking position in which a shaped surface of the latch obstructs the distal movement of the drive member when the latch is in the blocking position.

In disclosed embodiments, the latch is pivotable with respect to the cartridge assembly.

In disclosed embodiments, the latch includes a hook configured to engage a portion of the drive member to prevent distal translation of the drive member.

In disclosed embodiments, the latch includes a camming surface, and wherein when the drive member translates proximally into contact with the camming surface, the latch pivots away from its blocking position.

In disclosed embodiments, the surgical instrument comprises a sled configured for longitudinal translation with respect to at least a portion of the cartridge assembly. The sled includes a tail portion that is configured to abut a portion of the latch when the sled is adjacent its proximal-most position. The tail portion of the sled is configured to prevent the latch from moving into its blocking position.

The cartridge assembly may include a cartridge body defining a longitudinal slot. The drive member travels along the longitudinal slot in the distal direction. The shaped surface of the latch is substantially aligned with the longitudinal slot when the latch is in the blocking position.

BRIEF DESCRIPTION OF FIGURES

Various embodiments of the presently disclosed surgical instrument are disclosed herein with reference to the drawings, wherein:

<figref idref="DRAWINGS">FIG. 1</figref> is a perspective view of a surgical stapling instrument without a loading unit connected thereto in accordance with the present disclosure;

<figref idref="DRAWINGS">FIG. 1A</figref> is a perspective view of a loading unit in accordance with the present disclosure;

<figref idref="DRAWINGS">FIG. 1B</figref> is a perspective view of a tool assembly of the loading unit of <figref idref="DRAWINGS">FIG. 1A</figref>;

<figref idref="DRAWINGS">FIG. 1C</figref> is a perspective view of a cartridge assembly of the loading unit of <figref idref="DRAWINGS">FIG. 1A</figref>;

<figref idref="DRAWINGS">FIG. 1D</figref> is an assembly view of the tool assembly of <figref idref="DRAWINGS">FIG. 1B</figref>;

<figref idref="DRAWINGS">FIG. 2</figref> is a bottom perspective view of a portion of the tool assembly of <figref idref="DRAWINGS">FIG. 1B</figref>;

<figref idref="DRAWINGS">FIG. 3</figref> is a perspective view of a portion of the tool assembly of <figref idref="DRAWINGS">FIG. 1B</figref>;

<figref idref="DRAWINGS">FIGS. 4 and 5</figref> are transverse cross-sectional views of portions of the tool assembly of <figref idref="DRAWINGS">FIG. 1B</figref>;

<figref idref="DRAWINGS">FIG. 6</figref> is a perspective view of a proximal portion of a channel of the tool assembly of <figref idref="DRAWINGS">FIG. 1B</figref>;

<figref idref="DRAWINGS">FIG. 7</figref> is a perspective view of a distal portion of the channel of the tool assembly of <figref idref="DRAWINGS">FIG. 1B</figref>;

<figref idref="DRAWINGS">FIG. 8</figref> is a transverse cross-sectional view of portion of the tool assembly of <figref idref="DRAWINGS">FIG. 1B</figref>;

<figref idref="DRAWINGS">FIG. 9</figref> is a perspective view of the tool assembly of <figref idref="DRAWINGS">FIG. 1B</figref>;

<figref idref="DRAWINGS">FIG. 10</figref> is a perspective view of a support plate of the tool assembly of <figref idref="DRAWINGS">FIG. 1B</figref>;

<figref idref="DRAWINGS">FIG. 11</figref> is a perspective view of a distal portion of a cartridge body of the tool assembly of <figref idref="DRAWINGS">FIG. 1B</figref>;

<figref idref="DRAWINGS">FIG. 12</figref> is a perspective view of a proximal portion of the cartridge body of the tool assembly of <figref idref="DRAWINGS">FIG. 1B</figref>;

<figref idref="DRAWINGS">FIG. 13</figref> is a perspective view of a portion of a tool assembly of the present disclosure including another embodiment of a channel;

<figref idref="DRAWINGS">FIGS. 14 and 15</figref> are perspective views of the channel of <figref idref="DRAWINGS">FIG. 13</figref>;

<figref idref="DRAWINGS">FIGS. 16 and 17</figref> are perspective views of different portions of the channel of <figref idref="DRAWINGS">FIG. 13</figref>;

<figref idref="DRAWINGS">FIG. 18</figref> is a perspective view of a tool assembly of the present disclosure including a lockout mechanism;

<figref idref="DRAWINGS">FIG. 19</figref> is an enlarged perspective view of the lockout mechanism of the present disclosure engaged with a portion of the tool assembly;

<figref idref="DRAWINGS">FIG. 20</figref> is a perspective assembly view of portions of the tool assembly includes the lockout assembly;

<figref idref="DRAWINGS">FIG. 21</figref> is a perspective view of the lockout mechanism engaged with the channel;

<figref idref="DRAWINGS">FIG. 22</figref> is a perspective assembly view of the lockout mechanism and a portion of the channel;

<figref idref="DRAWINGS">FIG. 23</figref> is an assembly view of the removable assembly of an embodiment of the present disclosure;

<figref idref="DRAWINGS">FIG. 24</figref> is a perspective view of a latch of the lockout mechanism of the present disclosure;

<figref idref="DRAWINGS">FIG. 25</figref> is a perspective view of a sled of the present disclosure;

<figref idref="DRAWINGS">FIG. 26</figref> is a top view of the cartridge assembly taken along line <b>26</b>-<b>26</b> of <figref idref="DRAWINGS">FIG. 18</figref> and illustrating the lockout mechanism, and the drive member and sled in their original positions;

<figref idref="DRAWINGS">FIG. 27</figref> is an enlarged view of the area indicated in <figref idref="DRAWINGS">FIG. 26</figref>;

<figref idref="DRAWINGS">FIGS. 28-31</figref> are top views of a portion of the cartridge assembly showing the drive member, sled, and latch in various positions;

<figref idref="DRAWINGS">FIGS. 32-35</figref> are perspective views of a second embodiment of a lockout mechanism in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the presently disclosed surgical instrument, loading unit and tool assembly for use therewith, are described in detail with reference to the drawings, wherein like reference numerals designate corresponding elements in each of the several views. As is common in the art, the term ‘proximal” refers to that part or component closer to the user or operator, e.g., surgeon or physician, while the term “distal” refers to that part or component farther away from the user.

A surgical stapling instrument of the present disclosure is indicated as reference numeral <b>10</b> in <figref idref="DRAWINGS">FIG. 1</figref>. Additionally, the depicted surgical instrument fires staples, but it may be adapted to fire any other suitable fastener such as clips and two-part fasteners. A loading unit for use with surgical instrument <b>10</b> is shown in the accompanying figures and is indicated as reference number <b>500</b>. A tool assembly of the loading unit <b>500</b> is shown in the accompanying figures and is indicated as reference number <b>1000</b>.

Loading unit <b>500</b> is attachable to an elongated or endoscopic portion <b>18</b> of surgical instrument <b>10</b>, e.g., to allow surgical instrument <b>10</b> to have greater versatility. Loading unit <b>500</b> of the present disclosure is configured for to be used more than once. In particular, the loading unit has a removable assembly <b>1600</b> that includes the cartridge assembly <b>1200</b>. The cartridge assembly <b>1200</b> forms a part of the tool assembly <b>1000</b>, and the tool assembly <b>1000</b> forms a portion of the loading unit <b>500</b>. The removable assembly is configured to be removed and replaced (e.g., after firing fasteners therefrom). Examples of loading units for use with a surgical stapling instrument are disclosed in commonly-owned U.S. Pat. No. 5,752,644 to Bolanos et al., the entire contents of which are hereby incorporated by reference herein. The loading unit <b>500</b> shown includes a proximal body portion <b>502</b> that is attachable to an endoscopic portion or an elongated portion <b>18</b> of a surgical instrument <b>10</b> having a handle assembly <b>12</b>. However, the features of the loading units <b>500</b> of the present disclosure, including the tool assembly <b>1000</b>, can be incorporated in a surgical instrument in which does not include a detachable portion of the elongated portion of the instrument.

Loading unit <b>500</b> includes a proximal body portion <b>502</b> and a tool assembly <b>1000</b>. Proximal body portion <b>502</b> defines a longitudinal axis “A-A,” and is releasably attachable to a distal end of elongated portion <b>18</b> of surgical instrument <b>10</b>. Tool assembly <b>1000</b> includes a pair of jaw members including an anvil assembly <b>1100</b> and a cartridge assembly <b>1200</b>. One jaw member is pivotal in relation to the other to enable the clamping of tissue between the jaw members. In the illustrated embodiments, cartridge assembly <b>1200</b> is pivotal in relation to anvil assembly <b>1100</b> and is movable between an open or unclamped position and a closed or approximated position. However, the anvil assembly, or both the cartridge assembly and the anvil assembly, can be movable.

With reference to <figref idref="DRAWINGS">FIG. 1D</figref>, for example, anvil assembly <b>1100</b> includes an anvil cover <b>1110</b> and an anvil plate <b>1112</b>, which includes a plurality of staple forming depressions <b>1113</b>. Anvil plate <b>1112</b> is secured to an underside of anvil cover <b>1110</b> and defines a channel <b>1114</b> (see <figref idref="DRAWINGS">FIG. 8</figref>, for example) therebetween. When tool assembly <b>1000</b> is in the approximated position, staple forming depressions <b>1113</b> are positioned in juxtaposed alignment with staple receiving slots of the cartridge assembly <b>1200</b>.

The tool assembly includes a channel or carrier <b>1300</b> which receives and supports a cartridge assembly and a support plate <b>1500</b>. The cartridge assembly has a cartridge body <b>1400</b>. The cartridge body and support plate <b>1500</b> are attached to the channel or carrier <b>1300</b> by a snap-fit connection, as discussed below, a detent, latch, or by another type of connection. The cartridge assembly includes fasteners or staples <b>1414</b>. Cartridge body <b>1400</b> defines a plurality of laterally spaced staple retention slots <b>1410</b>, which are configured as openings in tissue contacting surface <b>1412</b> (see <figref idref="DRAWINGS">FIG. 11</figref>). Each slot <b>1410</b> is configured to receive a fastener or staple <b>1414</b> therein. Cartridge assembly <b>1200</b> also defines a plurality of cam wedge slots which accommodate staple pushers <b>1416</b> and which are open on the bottom (i.e., away from tissue-contacting surface <b>1412</b>) to allow an actuation sled <b>1418</b> to pass longitudinally therethrough.

Further details of the various components of cartridge assembly <b>1200</b>, including the connection between its various components, and the removability and replaceability of cartridge body <b>1400</b> and support plate <b>1500</b> with respect to channel <b>1300</b>, are discussed below. Generally, the removable assembly <b>1600</b> includes cartridge assembly <b>1200</b> and support plate <b>1500</b>. The removable assembly <b>1600</b> is removable from channel <b>1300</b>, e.g., after staples <b>1414</b> has been fired from cartridge body <b>1400</b>. Another removable assembly is capable of being loaded onto channel <b>1300</b>, such that surgical instrument <b>10</b> can be actuated again to fire additional fasteners or staples <b>1414</b>, for instance.

Channel <b>1300</b>, which may be machined (e.g., e.g., <b>1300</b><i>a </i>in <figref idref="DRAWINGS">FIGS. 13-17</figref>) or made of sheet metal (e.g., <b>1300</b><i>b </i>in <figref idref="DRAWINGS">FIG. 9</figref>), includes one or a pair of engagement structures or proximal bosses <b>1310</b> (e.g., <b>1300</b><i>b </i>in <figref idref="DRAWINGS">FIG. 6</figref>), a pair of cut-outs <b>1320</b> disposed adjacent a distal end, a pair of distal slots <b>1330</b>, a central slot <b>1340</b>, a pair of proximal holes <b>1350</b>, and a ramped surface <b>1360</b>. Proximal holes <b>1350</b> are configured to align with/mechanically engage a pair of corresponding holes <b>1120</b> (e.g., with a pin or protrusion extending through holes <b>1350</b> and holes <b>1120</b>) on anvil cover <b>1110</b> to facilitate a pivotal relationship between anvil assembly <b>1100</b> and cartridge assembly <b>1200</b>. It is envisioned that engagement structures <b>1310</b> may be pins, protrusions, or similar structure.

Cartridge body <b>1400</b> includes a central slot <b>1420</b>, and rows of staple retention slots <b>1410</b> positioned on each side of slot <b>1420</b> (see <figref idref="DRAWINGS">FIG. 11</figref>). In the illustrated embodiment, three rows of retention slots <b>1410</b> are shown. More specifically, cartridge body <b>1400</b> is configured such that actuation sled <b>1418</b> can pass through the cam wedge slots and force staple pushers <b>1416</b> towards anvil plate <b>1112</b>. The staples <b>1414</b>, which are supported on the pushers, are then forced out of their respective staple retention slots <b>1410</b>. Cartridge body <b>1400</b> also includes a pair of engagement structures or U-shaped recesses <b>1430</b> (which may, in other embodiments, be slots or openings) adjacent its proximal end, a pair of central bosses <b>1440</b>, a pair of distal protrusions <b>1450</b>, and a pair of distal grooves <b>1460</b>. Pairs of upper and lower mounting surfaces <b>1470</b>, <b>1480</b>, respectively, are disposed adjacent a proximal end of cartridge body <b>1400</b>, and are disposed adjacent respective upper and lower mounting slots <b>1472</b>, <b>1482</b>.

With particular reference to <figref idref="DRAWINGS">FIG. 10</figref>, support plate <b>1500</b> includes a base surface <b>1510</b>, a longitudinal slot <b>1520</b> extending through base surface <b>1510</b>, a pair of proximal fingers <b>1530</b> disposed and extending substantially perpendicularly from a proximal end of base surface <b>1510</b>, a pair of intermediate fingers <b>1550</b> extending substantially perpendicularly from a middle portion of base surface <b>1510</b>, a pair of inwardly-extending fingers <b>1560</b> and outwardly-extending bosses <b>1570</b> disposed adjacent a distal end of base surface <b>1510</b>, and a pair of proximal protrusions <b>1580</b> disposed adjacent the proximal end of base surface <b>1510</b>. Each proximal finger <b>1530</b> includes an engagement structure or proximal-facing U-shaped recesses <b>1532</b>, an upper mounting flange <b>1534</b>, and a lower mounting flange <b>1536</b>. As can be appreciated, support plate <b>1500</b> helps maintain pushers <b>1416</b> in place with respect to cartridge body <b>1400</b>. Additionally, longitudinal slot <b>1520</b> allows a portion of a drive member to pass through the support plate <b>1500</b>. The drive member may be a dynamic clamping member <b>1402</b>. The dynamic clamping member or drive member <b>1402</b> drives the actuation sled <b>1418</b> through the cartridge body <b>140</b>. The central slot of the cartridge body, the central slot of the channel, and the longitudinal slot of the support plate are all configured to align with one another to allow the passage of the drive member.

In use, to connect cartridge body <b>1400</b> and support plate <b>1500</b>, cartridge body <b>1400</b> and support plate <b>1500</b> are assembled or brought together such that the proximal-most end of cartridge is positioned between proximal fingers <b>1530</b> of support plate <b>1500</b> and in contact with base surface <b>1510</b> thereof. Support plate <b>1500</b> is then longitudinally translated (e.g., slid distally) with respect to cartridge body <b>1400</b> such that upper mounting flanges <b>1534</b> and lower mounting flanges <b>1536</b> engage upper mounting slots <b>1472</b> and lower mounting slots <b>1482</b>, respectively. The longitudinal translation between cartridge body <b>1400</b> and support plate <b>1500</b> continues until a distal-most end of proximal fingers <b>1530</b> contact a respective vertical wall <b>1490</b> (<figref idref="DRAWINGS">FIG. 12</figref>) of cartridge body <b>1400</b>. At this stage, U-shaped recesses <b>1430</b> are laterally adjacent and aligned with U-shaped recesses <b>1532</b> (see <figref idref="DRAWINGS">FIG. 3</figref>), and continued proximal movement of cartridge body <b>1400</b> with respect to support plate <b>1500</b> is prevented. Next, or concomitantly with the relative longitudinal translation between cartridge body <b>1400</b> and support plate <b>1500</b>, cut-outs <b>1552</b> within intermediate fingers <b>1550</b> of support plate <b>1500</b> are positioned around central bosses <b>1440</b> of cartridge, and inwardly-extending fingers <b>1560</b> are moved into engagement with distal grooves <b>1460</b> of cartridge. Cartridge assembly <b>1200</b> and support plate <b>1500</b> comprise a removable assembly <b>1600</b>, which is removable from and replaceable onto channel <b>1300</b> by the user of the surgical instrument <b>10</b> and/or loading unit <b>500</b>.

Removable assembly <b>1600</b> is insertable onto channel <b>1300</b> by approximating removable assembly <b>1600</b> and channel <b>1300</b> such that proximal bosses <b>1310</b> are positioned proximally of U-shaped recesses <b>1430</b> and <b>1532</b>, and such that distal ends of distal slots <b>1330</b> are positioned proximally of proximal ends of outwardly-extending bosses <b>1570</b>. Next, removable assembly <b>1600</b> is translated longitudinally (e.g., proximally) with respect to channel <b>1300</b> such that outwardly-extending bosses <b>1570</b> translate proximally within distal slots <b>1330</b> until proximal bosses <b>1310</b> contact U-shaped recesses <b>1430</b> and <b>1532</b>. Next, or concomitantly with the relative longitudinal translation between removable assembly <b>1600</b> and channel <b>1300</b>, cut-outs <b>1320</b> of channel <b>1300</b> are moved into engagement with distal protrusions <b>1450</b> of cartridge body <b>1400</b>. Ramped surface <b>1360</b> is engaged by the dynamic clamping member <b>1402</b> in order to move the anvil assembly <b>1100</b> and the cartridge assembly <b>1200</b> with respect to one another. A similar surface could be provided on the anvil assembly <b>1100</b>, in other embodiments. It is envisioned that ramped surface <b>1360</b> may also facilitate the alignment and/or engagement between channel <b>1300</b> and support plate <b>1300</b> and/or cartridge body <b>1400</b>.

Once assembled, a user is able to actuate movable handle <b>22</b> to eject staples <b>1414</b> from cartridge body <b>1400</b> and into tissue, as described below. It is envisioned that proximal protrusions <b>1580</b>, which extend from base surface <b>1510</b>, help maintain actuation sled <b>1418</b> in its relative position with respect to support plate <b>1500</b> before actuation of instrument <b>10</b>. That is, it is envisioned that actuation sled <b>1418</b>, or a portion thereof, is positioned proximally of proximal protrusions <b>1580</b>, and that proximal protrusions <b>1580</b> form a physically barrier to hinder any premature distal advancement of actuation sled <b>1418</b>. Once a user intends to actuate instrument <b>10</b> and distally advance actuation sled <b>1418</b> beyond proximal protrusions <b>1580</b>, the force used to advance actuation sled <b>1418</b> is sufficient to force a lower surface or portion of actuation sled <b>1418</b> over proximal protrusions <b>1580</b>.

After staples <b>1414</b> have been ejected from cartridge body <b>1400</b>, and a user wishes to use the same instrument <b>10</b> to fire additional staples <b>1414</b> (or another type of fastener or knife), the user can remove the removable assembly <b>1600</b> by sliding removable assembly <b>1600</b> distally with respect to channel <b>1300</b>. Next, a user removes the removable assembly <b>1600</b> from the channel <b>1300</b>. Another removable assembly with unfired staples can be loaded into the channel <b>1300</b>. In other embodiments, a cartridge body of a cartridge assembly can be removable from a support plate after the removable assembly is removed from the channel <b>1300</b>. The cartridge body is removed by sliding support plate <b>1500</b> proximally with respect to cartridge body <b>1400</b>. Another cartridge body, if desired, may be coupled to the support plate and inserted into the channel.

In certain embodiments, the removable assembly is part of a loading unit <b>500</b> that is removably attached to the elongated portion of a surgical stapling instrument, such as elongated portion <b>18</b>. This enables the user to choose a staple line length that is shorter or longer. It is also contemplated that the removable assembly can be used with a surgical instrument that does not have a loading unit that is removable and instead has jaws permanently attached to the elongated portion <b>18</b>.

During operation of stapler <b>10</b>, actuation of its movable handle <b>22</b> will fire the staples. The handle assembly <b>12</b> has an elongate actuation shaft that is translated distally when the movable handle <b>22</b> is pivotally moved by the user. The actuation shaft of the handle assembly can include teeth that are engaged by the movable handle <b>22</b>, or the handle assembly <b>12</b> can include a series of gears for moving the actuation shaft. Alternatively, the handle assembly can include a motorized driver for moving the actuation shaft, or the handle assembly can be attachable to a separate motorized driver.

In certain embodiments, through successive strokes of the movable handle, a drive rod <b>30</b> (a distal portion of which is illustrated in <figref idref="DRAWINGS">FIGS. 1 and 27-31</figref>)) is advanced distally, such that drive rod <b>30</b> pushes a portion of the drive assembly (which includes the dynamic clamping member <b>1402</b>) to translate distally through cartridge body <b>1400</b>. (Further details of how actuation of movable handle <b>22</b> causes distal advancement of drive rod <b>30</b> are explained in U.S. Pat. No. 6,953,139 to Milliman et al., which is hereby incorporated by reference herein.) Distal movement of the drive assembly, and in particular, the dynamic clamping member or drive member <b>1402</b>, causes approximation of one jaw member with respect to the other. That is, an upper portion of the dynamic clamping member <b>1402</b> travels through the channel <b>1114</b> between the anvil plate <b>1112</b> and the anvil cover <b>1110</b>, and a lower portion of the dynamic clamping member <b>1402</b> travels below the carrier <b>1300</b> of the cartridge assembly <b>1200</b>, which causes approximation of the anvil assembly <b>1100</b> and the cartridge assembly <b>1200</b> to clamp tissue therebetween. For example, the channel <b>1300</b> may have a lower surface defining a camming surface and the lower portion of the dynamic clamping member <b>1402</b> engages the camming surface to pivot the cartridge assembly <b>1200</b> toward the anvil assembly <b>1100</b>.

Additionally, distal translation of the dynamic clamping member <b>1402</b> causes the actuation sled <b>1418</b> to move distally through cartridge body <b>1400</b>, which causes cam wedges <b>1419</b> of actuation sled <b>1418</b> to sequentially engage pushers <b>1416</b> to move pushers <b>1416</b> vertically within staple retention slots <b>1410</b> and eject staples <b>1414</b> into staple forming depressions <b>1113</b> of anvil plate <b>1112</b>. Subsequent to the ejection of staples <b>1414</b> from retention slots <b>1410</b> (and into tissue), a cutting edge of the dynamic clamping member <b>1402</b> severs the stapled tissue as the cutting edge travels distally through central slot <b>1420</b> of cartridge body <b>1400</b>.

It is also envisioned, in further embodiments, that an end effector or tool assembly like the end effector or tool assembly <b>1000</b> is arranged for articulating between a first position where tool assembly <b>1000</b> is aligned with longitudinal axis “A-A,” and a second position where tool assembly <b>1000</b> is disposed at an angle with respect to longitudinal axis “A-A.” For example, the anvil assembly <b>110</b> may be pivotably attached to the proximal body portion <b>502</b> of a loading unit <b>500</b>, or pivotably attached to the elongated portion of the instrument. The loading unit includes one or more cables or linkages disposed in the proximal body portion <b>502</b> and attached at the tool assembly <b>1000</b>. When the cable or linkage is displaced, the tool assembly pivots and articulates with respect to the instrument. Further details of providing articulation are described in detail in commonly-owned U.S. Pat. No. 6,953,139 to Milliman et al., the contents of which has previously been incorporated by reference in their entirety. Further, the tool assembly can be configured not to articulate.

Additionally, it is envisioned that instrument <b>10</b> is powered by a power source and/or motor. Further details of such a powered surgical instrument are included in U.S. Patent Publication No. 2008/0255607, the entire contents of which are hereby incorporated by reference herein.

Further, and as illustrated in <figref idref="DRAWINGS">FIG. 11</figref>, for example, the present disclosure includes a cartridge body <b>1400</b> having a stepped tissue-contacting surface <b>1412</b>. In such an embodiment, different sized staples <b>1414</b>, or all the same sized staples, may be used. Further details of a staple cartridge having multiple staple sizes are included in U.S. Pat. No. 7,407,075 to Holsten et al., the entire contents of which are hereby incorporated by reference herein.

The present disclosure also relates to methods of using the described surgical instrument <b>10</b>, loading unit <b>500</b>, and tool assembly <b>100</b> to perform a surgical procedure and to methods of assembling the various components thereof, as described above.

With reference to <figref idref="DRAWINGS">FIGS. 18-35</figref>, two embodiments of a lockout mechanism <b>2000</b>, <b>2000</b><i>a </i>of the present disclosure are shown. For each of these embodiments, a surgical instrument having the lockout may have a channel, removable assembly, cartridge body, support plate, and the engagement structures discussed above. Furthermore, the present disclosure is directed to a removable assembly having the lockout, or a loading unit having the lockout.

With reference to <figref idref="DRAWINGS">FIGS. 18-31</figref>, the first embodiment of lockout mechanism <b>2000</b> includes a latch <b>2010</b> and a spring <b>2030</b>, and is configured to prevent re-firing of cartridge body <b>1400</b> of removable assembly <b>1600</b>, and also prevent distal translation of dynamic clamping member <b>1402</b> after an initial distal translation of knife and prior to another removable assembly <b>1600</b> being loaded onto channel <b>1300</b>.

With particular reference to <figref idref="DRAWINGS">FIGS. 22 and 24</figref>, latch <b>2010</b> includes a body <b>2012</b> having an upper surface <b>2014</b> and a lower surface <b>2016</b>, a lower protrusion <b>2018</b> depending downwardly from lower surface <b>2016</b>, a spring stop <b>2019</b> extending upwardly from upper surface <b>2014</b>, and a shaped surface <b>2020</b> on a first lateral side <b>2022</b>. The body <b>2012</b> also has a second lateral side <b>2024</b>. The shaped surface <b>2020</b> has two sides. The first side <b>2020</b><i>a </i>is angled with respect to the central slot <b>1340</b> when the latch <b>2010</b> is in a blocking position in which the latch obstructs the passage of the dynamic clamping member <b>1402</b>. The second side <b>2020</b><i>b </i>of the shaped surface <b>2020</b> extends transversely to the central slot <b>1340</b> when the latch is in the blocking position. (See <figref idref="DRAWINGS">FIG. 30</figref>).

Referring now to <figref idref="DRAWINGS">FIGS. 19-24</figref>, latch <b>2010</b> is mechanically engaged with channel <b>1300</b> so that the latch <b>2010</b> can pivot with respect to the channel <b>1300</b>. In particular, lower protrusion <b>2018</b> of latch <b>2010</b> (<figref idref="DRAWINGS">FIG. 24</figref>) extends through an opening <b>1380</b> (<figref idref="DRAWINGS">FIG. 22</figref>) in channel <b>1300</b>, such that latch <b>2010</b> is pivotable with respect to channel <b>1300</b>. Lower protrusion <b>2018</b> is maintained in mechanical engagement with channel <b>1300</b> by a lock pin <b>2050</b> (<figref idref="DRAWINGS">FIG. 22</figref>). Alternatively, the protrusion can be omitted and a separate pivot pin in engagement with the body <b>2012</b> and the channel <b>1300</b> can be used.

With regard to <figref idref="DRAWINGS">FIGS. 21-22</figref>, spring <b>2030</b> includes a first leg <b>2032</b>, a second leg <b>2034</b>, and an intermediate portion <b>2036</b> interconnecting first leg <b>2032</b> and second leg <b>2034</b>. First leg <b>2032</b> is in contact with a portion of channel <b>1300</b>. For example, the channel <b>1300</b> may have a slot <b>1301</b>, a notch, or some other feature for restricting the movement of the first leg <b>2032</b>. Second leg <b>2034</b> is disposed in contact with spring stop <b>2018</b> of latch <b>2010</b>. Intermediate portion <b>2036</b> is disposed between first leg <b>2032</b> and second leg <b>2034</b>. For example, the spring may have a U-shaped configuration (see <figref idref="DRAWINGS">FIG. 27</figref>), or some other shape, such as L-shaped.

Spring <b>2030</b> is in mechanical cooperation with a portion of the cartridge assembly <b>1200</b>. The spring is configured to bias latch <b>2010</b> towards its blocking position. In the initial position of the dynamic clamping member <b>1402</b> and the sled <b>1418</b> (e.g., prior to distal advancement thereof to fire staples and incise tissue), a tail portion <b>1417</b> of sled <b>1418</b> (<figref idref="DRAWINGS">FIG. 25</figref>) physically prevents the shaped surface <b>2020</b> of latch <b>2010</b> from moving from its initial position into its blocking position, and thus allows distal translation of dynamic clamping member <b>1402</b> and sled <b>1418</b> (see <figref idref="DRAWINGS">FIGS. 26 and 27</figref>). After translation of the dynamic clamping member and sled, the spring moves the latch <b>2010</b> to the blocking position, where the shaped surface <b>2020</b> of latch <b>2010</b> obstructs the central slot <b>1340</b> of channel <b>1300</b> and the longitudinal slot <b>1520</b> extending through base surface <b>1510</b> of support plate <b>1500</b> (see <figref idref="DRAWINGS">FIGS. 30 and 31</figref>), such that shaped surface <b>2020</b> would block distal translation of dynamic clamping member <b>1402</b> when the dynamic clamping member <b>1402</b> has been retracted after firing staples and cutting tissue.

The latch <b>2010</b> is laterally movable from an initial position to a blocking position. The latch moves laterally, which enables the shaped surface of the latch to obstruct the slot and move away from a position that obstructs the slot of the cartridge assembly.

During retraction of the dynamic clamping member, the dynamic clamping member slides along the shaped surface first side <b>2020</b><i>a</i>, keeping the latch <b>2010</b> away from the dynamic clamping member and pivoting the latch against the bias of the spring. In the retracted position of the dynamic clamping member, it is disposed proximally of shaped surface <b>2020</b> and the sled <b>1418</b> and/or tail portion <b>1417</b> is not abutting the shaped surface <b>2020</b>. The latch <b>2010</b> pivots to the blocking position, so that the second side <b>2020</b><i>b </i>obstructs and/or prevents distal movement of the dynamic clamping member.

During distal advancement of dynamic clamping member <b>1402</b> and sled <b>1418</b>, and after sled <b>1418</b> distally passes latch <b>2010</b> such that shaped surface <b>2020</b> is no longer in contact with tail portion of sled <b>1418</b>, dynamic clamping member <b>1402</b> abuts the shaped surface <b>2020</b>, which physically blocks latch <b>2010</b> from moving into its blocking position, and thus permits distal translation of dynamic clamping member <b>1402</b> (see <figref idref="DRAWINGS">FIG. 28</figref>).

When cartridge assembly <b>1200</b> or removable assembly <b>1600</b> is removed from channel <b>1300</b>, latch <b>2010</b> continues to block dynamic clamping member <b>1402</b> (see <figref idref="DRAWINGS">FIG. 31</figref>). When a new cartridge assembly <b>1200</b> or removable assembly <b>1600</b> is loaded onto channel <b>1300</b>, tail portion <b>1417</b> of the new sled <b>1418</b> engages shaped surface first side <b>2020</b><i>a </i>of latch <b>2010</b> and pivots latch <b>2010</b> away from its blocking position. Without a sled having the correct configuration, the latch remains in the blocking position.

With reference to <figref idref="DRAWINGS">FIGS. 32-35</figref>, a second embodiment of lockout mechanism <b>2000</b><i>a </i>is shown. A surgical instrument having the lockout may have a channel, removable assembly, cartridge body, support plate, and the engagement structures discussed above. Furthermore, the present disclosure is directed to a removable assembly having the lockout, or a loading unit having the lockout. Lockout mechanism <b>2000</b><i>a </i>includes a latch <b>2010</b><i>a</i>, and a spring. The spring is not shown for clarity, but may be as discussed above. Unlike the embodiment of lockout mechanism <b>2000</b> discussed above, this embodiment of lockout mechanism <b>2000</b><i>a </i>does not include a lock pin <b>2050</b>. Here, to maintain latch <b>2010</b><i>a </i>in engagement with channel <b>1300</b><i>a</i>, lower surface <b>2016</b><i>a </i>of latch <b>2010</b><i>a </i>includes a locking member <b>2018</b><i>a </i>depending therefrom.

In the illustrated embodiment, locking member <b>2018</b><i>a </i>includes a pair of parallel walls that are interconnected by a pair of arcuate walls. The opening <b>1380</b><i>a </i>of channel <b>1300</b><i>a </i>includes similar, but slightly larger shape with respect to locking member <b>2018</b><i>a </i>and also includes a circular recess <b>1381</b><i>a</i>, around which locking member <b>2018</b><i>a </i>can rotate (see <figref idref="DRAWINGS">FIGS. 34 and 35</figref>).

To engage latch <b>2010</b><i>a </i>with channel <b>1300</b><i>a</i>, locking member <b>2018</b><i>a </i>is inserted through opening <b>1380</b><i>a </i>and latch <b>2010</b><i>a </i>is then rotated a predetermined amount (e.g., about 40 degrees to about 130 degrees) such that latch <b>2010</b><i>a </i>does not fall through opening <b>1380</b><i>a </i>of channel <b>1300</b><i>a</i>. The spring (not shown in this embodiment for clarity) may then be positioned between spring stop <b>2018</b><i>a </i>of latch <b>2010</b><i>a </i>and a portion of channel <b>1300</b><i>a</i>, as described above.

As can be appreciated, use of surgical instrument including the second embodiment of lockout mechanism <b>2000</b><i>a </i>is similar to, or that same as use of the surgical instrument including the first embodiment of lockout mechanism <b>2000</b>, as described above.

While the above description contains many specifics, these specifics should not be construed as limitations on the scope of the present disclosure, but merely as illustrations of various embodiments thereof. Therefore, the above description should not be construed as limiting, but merely as exemplifications of various embodiments.

Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.